Pulsed flow atmospheric real-time ionization

Abstract

In this embodiment of the environmental ionization experiment, the abundance of background chemicals relative to the target ions is reduced by pulsed application of the carrier gas used to generate the excited substance directed toward the sample. The excited substance is progressively directed toward the sample, thereby reducing the overall abundance of background chemicals introduced into the ionization region. In this embodiment of the environmental ionization experiment, the combination of sample stepping before the excited substance and pulsed application of the carrier gas used to generate the excited substance improves the detection sensitivity.

Description

Technical Field

[0001] This invention relates to a method and apparatus for chemical analysis of molecules ionized in ambient atmosphere by introducing a carrier gas via pulse. Background Technology

[0002] Analysis of target molecules in the ambient atmosphere of a laboratory or field setting can be accomplished by using ionizing substances to convert the target molecules into ions and then guiding or removing the ions into the spectrometer. However, the ambient atmosphere in a laboratory or field setting may contain many "background chemicals" that can also be detected. These background chemicals can vary depending on the local environment. For example, trace chemicals present in a laboratory atmosphere may include solvents, dust particles, aerosols, counterions, and chemicals used in synthesis or extraction. In addition, the background can include chemicals from human, animal, bacterial, viral, or fungal activity (including the presence of the spectrometer operator / scientist), including chemicals from respiration, perfumes, fragrances, mouthwash, cosmetics, sweat, flatulence, bacterial gases, and bacterial odors. The presence of any one or more of these can lead to the formation of a persistent background. When the background becomes too rich, the process of ambient ionization and ion detection of target molecules may become inefficient because the target molecules may not be detected, or their abundance may be so low that they are masked by the detection of background chemicals.

[0003] Trace chemicals present in the target sample can also be considered background chemicals because they are present in the ionization region but are not the target. These substances include chemicals originating from the sample container, solvent residues, chemicals that are normally present but not important for the characterization of the sample, and chemicals that may be introduced into the air surrounding the ionized material, including those from human activities, such as solvents, or from other nearby analytical work. For example, in urine samples, the metabolite creatinine, a chemical waste produced by muscle metabolism, is readily ionized and detected by a spectrometer. The kidneys filter creatinine and other waste products (including urea) from circulating blood, allowing them to be excreted from the body through urination. Therefore, both compounds (creatinine and urea) are present as background chemicals when analyzing human fluids. Furthermore, urea itself is difficult to extract from urine, which is why the analysis of abused drugs in workplace drug testing is often performed by separating urea from the target molecules using chromatographic materials. Chromatographic materials delay the passage of larger drug molecules while allowing urea to be directed to waste. In the absence of urea, larger drug molecules are ionized in the ambient atmosphere and are readily detectable after entering the spectrometer.

[0004] Solvent effects can also contribute to background chemicals, such as solvents used to dissolve the sample, like dimethyl sulfoxide (DMSO), and chemicals added to the sample to promote pH changes or ionization buffers can also contribute to background chemicals.

[0005] In theory and practice, eliminating background chemicals before environmental ionization reduces background chemical ions, i.e., chemical noise, thereby allowing for increased sensitivity to target molecules. Summary of the Invention

[0006] In embodiments of the invention, in an ambient ionization experiment, pulsed application of the carrier gas used to generate the ionized substance can be used to increase the ionization of the target molecule, thereby allowing for a reduction in the detection limit. In embodiments of the invention with an ambient ionization experiment, hopping from one location and pulsed application of the carrier gas used to generate the ionized substance can be used to increase the ionization of the target molecule, thereby allowing for a reduction in the detection limit. Attached Figure Description

[0007] Unless otherwise specified, all direct real-time analysis (DART) atmospheric pressure ionization (API) measurements were performed at 300°C. All samples were spotted using a TTP Labtech Mosquito (a positive displacement pipette). All mass spectrometry analyses were performed at Thermo Scientific. TM The company's Q-Exactive TM The experiment was conducted on a mass spectrometer. Various embodiments of the invention will be described in detail based on the following figures, wherein:

[0008] Figure 1 According to various embodiments of the invention, the paper consumable retains a wire mesh in a blank inserted into an XY actuator designed to present a series of samples deposited at regular intervals (1 to 12) on the surface of the mesh to ionized material emitted from a remote end of a DART API source.

[0009] Figure 2A This is a schematic diagram of ionized material from a DART API source passing through a narrow cap and being guided to a sample, which is applied to a mesh inserted into the ionization volume of a spectrometer, according to various embodiments of the present invention.

[0010] Figure 2B This is a schematic diagram of ionized material from a DART API source passing through an elongated cap and being guided to a sample, which is applied to a mesh inserted into the ionization volume of a spectrometer, according to various embodiments of the present invention.

[0011] Figure 3The graph shows the relative helium consumption of three (3) different experiments for presenting samples: continuously at 3 mm / s, which is referred to below as “Continuous Ionization Experiment (CIE)”; in the mixed mode, which involves discontinuous sample presentation, wherein the carrier gas is turned off before sample presentation and then turned on for three (3) seconds while presenting the sample, moving at 3 mm / s, and then stopping until the next sample is presented for analysis, which is referred to below as “Mixed Experiment (HE)”; and in the pulsed mode, which involves discontinuous sample presentation, wherein the carrier gas is turned off before sample presentation and then turned on for one (1) second while the sample is presented statically (i.e., without moving), and then turned off before the next sample is presented for analysis, which is referred to below as “Pulse Experiment (PE)”;

[0012] Figure 4A Fentanyl (single ion monitoring (hereinafter referred to as SIM) 337.2 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) was subjected to positive DART API CIE mass chromatography. The mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein scans were performed at all twelve (12) sample positions and obtained using a 1.0 mm exit cap, which is referred to below as "(with 1.0 mm exit cap)".

[0013] Figure 4B Positive DART API CIE mass chromatography (with a 1.0 mm exit cap) of cocaine (SIM 304.3 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), codeine (0.01 mg / mL), and methamphetamine, the mixture was applied to a network (eight (8) repeat positions, repeat positions 3 to 10), wherein scanning was performed at all twelve (12) sample positions;

[0014] Figure 4C The positive DART APICIE (with a 1.0 mm outlet cap) mass chromatography of codeine (SIM 300.3 ± 0.5 Da) present in a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) and methamphetamine in a 200 nL volume was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein scanning was performed at all twelve (12) sample positions;

[0015] Figure 4D The positive DART API CIE (with a 1.0 mm exit cap) total ion current (TIC) trace of a 200 nL volume mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was obtained by applying the mixture to a grid (eight (8) repeating positions from position 3 to 10), where scanning was performed at all twelve (12) sample positions.

[0016] Figure 5A The positive DART API CIE mass chromatography of fentanyl (SIM 337.2 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was performed on a network (eight (8) repeat positions in positions 3 to 10), wherein scans were performed at all twelve (12) sample positions and obtained using a 2.5 mm exit cap, which is referred to below as "(with 2.5 mm exit cap)";

[0017] Figure 5B The positive DART API CIE (with a 2.5 mm exit cap) mass chromatography of cocaine (SIM 304.3 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL), was performed on a network (eight (8) replicate positions from position 3 to 10), with scans performed at all twelve (12) sample positions.

[0018] Figure 5C The positive DART APICIE (with a 2.5 mm outlet cap) mass chromatography of codeine (SIM 300.3 ± 0.5 Da) present in a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) and methamphetamine in a 200 nL volume was performed. The mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), where scans were performed at all twelve (12) sample positions.

[0019] Figure 5D It is a positive DART API CIE (with a 2.5 mm exit cap) TIC trace of a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL), which was applied to a net (eight (8) repeat positions from position 3 to 10), where scanning was performed at all twelve (12) sample positions;

[0020] Figure 6A According to an embodiment of the present invention, positive DART API HE mass chromatography (with a 1.0 mm outlet cap) was performed on a net (eight (8) replicate positions from positions 3 to 10) for fentanyl (SIM 337.2 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL), wherein HE was performed on all 12 sample positions;

[0021] Figure 6B According to an embodiment of the present invention, positive DART API HE (with a 1.0 mm outlet cap) mass chromatography of cocaine (SIM 304.3 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was performed on a network (eight (8) repeat positions from position 3 to 10), wherein HE was performed on all 12 sample positions;

[0022] Figure 6C According to an embodiment of the present invention, positive DART API HE (with a 1.0 mm outlet cap) mass chromatography of codeine (SIM30 0.3 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) and methamphetamine, the mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein HE was performed on all 12 sample positions;

[0023] Figure 6D The positive DART API HE (with a 1.0 mm outlet cap) TIC trace of a mixture of 200 nL volume of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) according to an embodiment of the present invention, the mixture being applied to a net (eight (8) repeating positions from position 3 to 10), wherein HE is performed on all 12 sample positions;

[0024] Figure 7AAccording to an embodiment of the present invention, positive DART API HE (with a 2.5 mm outlet cap) mass chromatography of fentanyl (SIM 337.2 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was performed on a network (eight (8) repeat positions from position 3 to 10), wherein HE was performed on all 12 sample positions;

[0025] Figure 7B According to an embodiment of the present invention, positive DART API HE (with a 2.5 mm outlet cap) mass chromatography of cocaine (SIM 304.3 ± 0.5 Da) present in a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) in a volume of 200 nL, the mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein HE was performed on all 12 sample positions;

[0026] Figure 7C According to an embodiment of the present invention, positive DART API HE (with a 2.5 mm outlet cap) mass chromatography of codeine (SIM30 0.3 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) and methamphetamine, the mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein HE was performed on all 12 sample positions;

[0027] Figure 7D The positive DART API HE (with a 2.5 mm outlet cap) TIC trace of a mixture of 200 nL volume of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) according to an embodiment of the present invention, the mixture being applied to a net (eight (8) repeating positions from position 3 to 10), wherein HE is performed on all 12 sample positions;

[0028] Figure 8A According to an embodiment of the present invention, positive DART API PE (with a 1.0 mm outlet cap) mass chromatography of fentanyl (SIM 337.2 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was performed on a network (eight (8) replicate positions from position 3 to 10), wherein PE was performed on all 12 sample positions;

[0029] Figure 8B According to an embodiment of the present invention, positive DART API PE (with a 1.0 mm outlet cap) mass chromatography of cocaine (SIM 304.3 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was performed on a network (eight (8) replicate positions from position 3 to 10), wherein PE was performed on all 12 sample positions;

[0030] Figure 8C According to an embodiment of the present invention, positive DART API PE (with a 1.0 mm outlet cap) mass chromatography of codeine (SIM30 0.3 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) and methamphetamine, the mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein PE was performed on all 12 sample positions;

[0031] Figure 8D The positive DART API PE (with a 1.0 mm outlet cap) TIC trace of a mixture of 200 nL volume of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) according to an embodiment of the present invention, the mixture being applied to a net (eight (8) repeating positions from position 3 to 10), wherein PE is performed on all 12 sample positions;

[0032] Figure 9A According to an embodiment of the present invention, positive DART API PE (with a 2.5 mm outlet cap) mass chromatography of fentanyl (SIM 337.2 ± 0.5 Da) present in a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) was performed on a network (eight (8) replicate positions from position 3 to 10), wherein PE was performed on all 12 sample positions;

[0033] Figure 9BAccording to an embodiment of the present invention, positive DART API PE (with a 2.5 mm outlet cap) mass chromatography of cocaine (SIM 304.3 ± 0.5 Da) present in a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) in a volume of 200 nL, the mixture being applied to a network (eight (8) replicate positions in positions 3 to 10), wherein PE is performed on all 12 sample positions;

[0034] Figure 9C According to an embodiment of the present invention, positive DART API PE (with a 2.5 mm outlet cap) mass chromatography of codeine (SIM30 0.3 ± 0.5 Da) present in a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) and methamphetamine, the mixture was applied to a network (eight (8) repeat positions in positions 3 to 10), wherein PE was performed on all 12 sample positions;

[0035] Figure 9D The positive DART API PE (with a 2.5 mm outlet cap) TIC trace of a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL) according to an embodiment of the present invention, the mixture being applied to a net (eight (8) repeating positions from position 3 to 10), wherein PE is performed on all 12 sample positions;

[0036] Figure 10 It shows the relationship with Figure 4D Compared to (solid line), Figure 4A (short dash) Figure 4B (long underline) Figure 4C The SIM response time is between 0.62 and 0.66 minutes, as shown by the dotted line.

[0037] Figure 11A It is a DART API CIE (with a 2.5 mm exit cap) TIC in which the sample is a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL), which is applied to the net (eight (8) repeat positions in positions 3 to 10);

[0038] Figure 11BThe present invention is a DART API PETIC (with a 2.5 mm outlet cap) according to an embodiment of the present invention, wherein the sample is a 200 nL volume of a mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL) and codeine (0.01 mg / mL), which is applied to a net (eight (8) repeating positions from position 3 to 10);

[0039] Figure 12A The mass chromatography of fentanyl (SIM 337.2 ± 0.5 Da) in a 200 nL volume mixture of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL) according to an embodiment of the present invention was performed using DART API PE (with a 2.5 mm outlet cap), the mixture being applied to a network (eight (8) replicate positions from position 3 to 10);

[0040] Figure 12B The present invention relates to an embodiment of a DART API PE (with a 2.5 mm exit cap) TIC trace of a mixture of 200 nL of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL), applied to a mesh (eight (8) repeating positions from positions 3 to 10), wherein the sample as... Figure 12A What is presented;

[0041] Figure 13A This is an embodiment of the present invention, showing the DART API PE (with a 2.5 mm exit cap) mass spectrometry of caffeine (SIM 195.1 ± 0.5 Da) present in a 200 nL volume mixture of cocaine (1 mg / mL), lidocaine (1 mg / mL), and methadone (1 mg / mL), applied to a net sample presented in 1536 template format;

[0042] Figure 13B The present invention relates to an embodiment of the DART API PE (with a 2.5 mm exit cap) mass spectrometry of lidocaine (SIM 235.2 ± 0.5 Da) present in a mixture of caffeine (1 mg / mL), cocaine (1 mg / mL) and methadone (1 mg / mL) in a volume of 200 nL, the mixture being applied to a net sample presented in 1536 template format;

[0043] Figure 13CAccording to an embodiment of the present invention, cocaine (SIM 304.3±0.5 Da) present in a mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL) and methadone (1 mg / mL) in a volume of 200 nL was subjected to DART API PE (with a 2.5 mm exit cap) mass spectrometry, which was applied to a net sample presented in 1536 template format;

[0044] Figure 13D This is a DART API PE (with a 2.5 mm exit cap) mass spectrometry of methadone (SIM 310.2±0.5 Da) present in a mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL) and cocaine (1 mg / mL) in a volume of 200 nL, which was applied to a net sample presented in 1536 template format according to an embodiment of the present invention.

[0045] Figure 14A According to an embodiment of the present invention, caffeine (SIM 195.1 ± 0.5 Da) present in a mixture of cocaine (1 mg / mL), lidocaine (1 mg / mL) and methadone (1 mg / mL) in a volume of 200 nL was subjected to DART API PE (with a 2.5 mm outlet cap) mass chromatography on a sample presented in a 1536 template format (twelve (12) replicate positions from position 1 to 12);

[0046] Figure 14B According to an embodiment of the present invention, lidocaine (SIM 235.2 ± 0.5 Da) present in a mixture of caffeine (1 mg / mL), cocaine (1 mg / mL) and methadone (1 mg / mL) in a volume of 200 nL was subjected to DART API PE (with a 2.5 mm exit cap) mass chromatography on a sample presented in a 1536 template format (twelve (12) replicate positions from position 1 to 12);

[0047] Figure 14C According to an embodiment of the present invention, cocaine (SIM 304.3 ± 0.5 Da) present in a mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL) and methadone (1 mg / mL) in a volume of 200 nL was subjected to DART API PE (with a 2.5 mm exit cap) mass chromatography on a sample presented in a 1536 sample format (twelve (12) replicate positions from position 1 to 12);

[0048] Figure 14DAccording to an embodiment of the present invention, methadone (SIM 310.2±0.5Da) present in a mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL) and cocaine (1 mg / mL) in a volume of 200 nL was subjected to DART API PE (with a 2.5 mm outlet cap) mass chromatography on a sample presented in a 1536 template format (twelve (12) replicate positions from position 1 to 12);

[0049] Figure 14E The samples of methadone (1 mg / mL), caffeine (1 mg / mL), lidocaine (1 mg / mL) and cocaine (1 mg / mL) according to embodiments of the present invention were applied to a net (twelve (12) repeating positions from position 1 to 12) of samples presented in 1536 template format;

[0050] Figure 15A This is a line drawing of a pipetting robot (1504) according to an embodiment of the present invention, which is used to deliver small-volume samples to, for example... Figure 16A The surface of the QuickStrip-96 wire mesh shown;

[0051] Figure 15B This is a line drawing of a DART API source installed in a vertical position according to an embodiment of the present invention, wherein the GIS interface is connected to the quality detector at a 90-degree angle, as shown. Figure 16B As shown;

[0052] Figure 16A The pipetting head of the TTP Labtech Mosquito robot (1504) according to an embodiment of the present invention has a series of 16 positive displacement pipettes (1523) for delivering small volume samples onto the surface of a QuickStrip-96 wire mesh consumable (1532) mounted on its sampling stage (1543);

[0053] Figure 16B It is a DART API source installed in a vertical position according to an embodiment of the present invention, wherein the 2.5mm exit cap is in a straight line with the GIS interface connected to the quality detector at a 90-degree angle;

[0054] Figure 16C This is a DART API source installed in a vertical position according to an embodiment of the present invention, wherein the 2.5mm outlet cap is aligned with the GIS interface connected to the quality detector at a 90-degree angle; and

[0055] Figure 16DIt is a DART API source installed in a vertical position according to an embodiment of the present invention, wherein the 2.5mm outlet cap is in a straight line with the GIS interface, which is connected to a smooth continuous tube surface at a 90-degree angle to the quality detector. Detailed Implementation

[0056] Abbreviations include:

[0057] API = Atmospheric Pressure Ionization; CIE = Continuous Ionization Experiment; DART = Direct Real-Time Analysis; DESI = Desorption Electrospray Ionization; DMS = Differential Mobility Spectrometer; ESI = Electrospray Ionization; GIS = Gas Ion Separator; HE = Mixing Experiment; RS = Active Substance; PE = Pulse Experiment; SIM = Single Ion Monitoring; TIC = Total Ion Current.

[0058] Definitions of some terms used below include:

[0059] The transitional term “comprising” is synonymous with “including,” “containing,” or “characterized by,” and is inclusive or open-ended, and does not exclude additional, unlisted elements or method steps.

[0060] The transitional phrase “composed of” does not include any element, step or ingredient not specified in the claims, but does not exclude other components or steps unrelated to the invention, such as impurities typically associated with the composition.

[0061] The transitional phrase “consistent essentially of…” limits the scope of the claim to the specified materials or steps and to materials or steps that do not substantially affect the essential and novel features of the claimed invention.

[0062] The term Gas-Ion Separator (GIS) will be used to refer to a device that separates ions from one or two neutral molecules and neutral atoms to allow for the pre-concentration and transfer of ions to an analytical system. The term "inlet tube" will be used to refer to the low-vacuum side of the GIS. The term "outlet tube" will be used to refer to the high-vacuum side of the GIS. In various embodiments of the invention, the tube may be an inlet tube. Active ionization refers to the process of ionizing analyte ions using an atmospheric analyzer that does not utilize radioactive nuclei. A capacitive surface is a surface that can be charged with a potential. A surface can be charged with a potential if the potential applied to it remains constant over a typical duration of the experiment, wherein the potential at the surface is greater than 50% of the potential applied to the surface. The vacuum level at atmospheric pressure is approximately 760 Torr. Here, "approximately" encompasses values ​​from below 10... 1 Atmosphere = 7.6 × 10 3 Up to 10 -1 Atmosphere = 7.6 × 10 1 Pressure range of Torr. Below 10 -3The vacuum level of Torr will constitute a high vacuum. Here, "approximately" covers values ​​from below 5 × 10⁻⁶. -3 Up to 5×10 -6 Pressure range of Torr. Below 10 -6 The vacuum level achieved by Torr will constitute an ultra-high vacuum. Here, "approximately" encompasses vacuums below 5 × 10⁻⁶. -6 Up to 5×10 -9 The pressure range of Torr. In the following text, the phrase "high vacuum" encompasses both high vacuum and ultra-high vacuum.

[0063] The term "contact" is used to refer to any process in which sample molecules in one or more of the gas, liquid, and solid phases are adsorbed, absorbed, or chemically bound to a surface.

[0064] A grating is "coated" with substrate when the process causes substrate molecules to be adsorbed, absorbed, or chemically bound to the surface. A grating can be coated when droplets are adsorbed, absorbed, or chemically bound to it. A grating can be coated when nanodroplets are adsorbed, absorbed, or chemically bound to it.

[0065] A filament refers to one or more of the following: metal wire loops, metal wire segments, metal strips, metal strands or non-insulating metal wires, animal thread, paper, perforated paper, fiber, cloth, silica, fused silica, plastic, plastic foam, polymer, Teflon, polymer-impregnated Teflon, cellulose, and filaments coated and impregnated with hydrophobic support materials. In various embodiments of the invention, the filament has a diameter of about 50 micrometers to about 2 millimeters. When measuring the diameter of the filament, approximately plus or minus twenty percent is indicated (20). In one embodiment of the invention, the length of the filament is about 1 mm to about 25 mm. When measuring the length of the filament, approximately plus or minus twenty percent is indicated (20).

[0066] The term "orientation" refers to the position of the mesh relative to another segment of the mesh or relative to the grid or sample holder. In embodiments of the invention, the mesh, grid, or sample holder can be mounted on an XY translation stage so that a sample at a point on the mesh can be accurately oriented relative to the ionized material. Control electronics and stepper motor drivers for the XY platform can be directly mounted on the housing that houses the XY translation stage, while the microcontroller controlling the orientation can be mounted separately.

[0067] The term "proximity" refers to the location of a network or area on a network relative to another network or other area on a network.

[0068] The term "registration" refers to the alignment of a region of the mesh (e.g., the proximal region) with the mesh to deliver heat from the mesh to the proximal region of the tooth.

[0069] The term "contact" refers to the gathering or touching of objects or surfaces, such as sampling a surface with a mesh area.

[0070] The shape of the mesh can be a cylinder, an elliptical cylinder, a long square block, a long rectangular block, or a long thin surface.

[0071] The term "hole" refers to a hollow space within another solid object that has an opening that allows light and / or particles to pass through that solid object. A hole can be circular, elliptical, pear-shaped, a slit, or polygonal (including triangular, square, rectangular, pentagonal, hexagonal, heptagonal, etc.).

[0072] In the context of thermal atoms and / or thermal molecules, the term "thermal" refers to a substance having a velocity corresponding to a temperature above ambient (273 K). In embodiments of the invention, the thermal substance has velocities corresponding to temperatures of 300 K, 400 K, and 500 K.

[0073] The term "continuous flow" carrier gas refers to a constant flow of carrier gas entering the discharge chamber. The term "mixed flow" carrier gas refers to a flow of carrier gas entering the discharge chamber that is pulsed when the linear guide moves within a measurement time interval; otherwise, no carrier gas enters the discharge chamber. The term "pulsed flow" carrier gas refers to a flow of carrier gas entering the discharge chamber that is pulsed when the linear guide stops for a period of time; otherwise, no carrier gas enters the discharge chamber.

[0074] The term "corona discharge" refers to a discharge occurring at relatively high atmospheric pressure (e.g., at atmospheric pressure) in a highly non-uniform electric field (e.g., by placing a thin metal wire inside a metal cylinder with a radius much larger than the wire). The electric field is high enough to ionize the gas surrounding the wire, but insufficient to cause electrical breakdown or arcing in nearby conductors. The term "arc discharge" refers to a discharge that relies on the thermionic emission of electrons from electrodes supporting the arc, and is characterized by a voltage lower than that of a glow discharge but with a strong current. The term "glow discharge" refers to a discharge generated by secondary electron emission.

[0075] The term "first atmosphere chamber" refers to a chamber that is approximately at atmospheric pressure.

[0076] The term "discharge" refers to one or more of the following: corona discharge, arc discharge, and glow discharge.

[0077] Metals comprise one or more of the following elements: lithium, beryllium, boron, carbon, nitrogen, oxygen, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, potassium, calcium, scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, arsenic, selenium, rubidium, strontium, yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver, cadmium, indium, tin, antimony, tellurium, cesium, barium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, mercury, thallium, lead, bismuth, polonium, francium, and radium. Therefore, metals include, for example, nickel-titanium alloys known as nitinol or ferrochrome alloys used to manufacture stainless steel.

[0078] Plastics include one or more of the following: polystyrene, high-impact polystyrene, polypropylene, polycarbonate, low-density polyethylene, high-density polyethylene, polypropylene, acrylonitrile butadiene styrene, polyphenylene ether alloyed with high-impact polystyrene, expanded polystyrene, polyphenylene ether and polystyrene impregnated with pentane, and blends of polyphenylene ether and polystyrene impregnated with pentane or polyethylene and polypropylene.

[0079] The polymer comprises a material synthesized from one or more reagents selected from the group consisting of: styrene, propylene, carbonates, ethylene, acrylonitrile, butadiene, vinyl chloride, vinyl fluoride, polyethylene terephthalate, terephthalate, dimethyl terephthalate, bis-β-terephthalate, naphthalenedicarboxylic acid, 4-hydroxybenzoic acid, 6-hydroxynaphthalene-2-carboxylic acid, monoethylene glycol (1,2-ethylene glycol), cyclohexyl-diethanol, 1,4-butanediol, 1,3-butanediol, polyester, cyclic... Hexanediol, terephthalic acid, isophthalic acid, methylamine, ethylamine, ethanolamine, dimethylamine, hexanediamine (hexane-1,6-diamine), pentanediamine, methylethanolamine, trimethylamine, aziridine, piperidine, N-methylpiperidine, anhydrous formaldehyde, phenol, bisphenol A, cyclohexanone, trioxane, dioxolane, ethylene oxide, adipic acid chloride, adipic acid, butylated oxalate, sebacic acid, glycolic acid, lactide, caprolactone, aminocaproic acid, and / or blends of two or more materials synthesized by polymerization from these reagents.

[0080] Plastic foams are polymers or plastics that trap gas bubbles, including polyurethane, expanded polystyrene, phenolic foam, XPS foam, and quantum foam.

[0081] "Mesh" refers to one or more of the following: two or more connecting filaments, two or more connecting wires, foam, perforated paper, screen, paper screen, plastic screen, fiber screen, cloth screen, polymer screen, silica screen. (Polytetrafluoroethylene (PVDF)) screens, polymer-impregnated Teflon screens, and cellulose screens. In various embodiments of the invention, the screen comprises one or more of the following: three or more connecting filaments, three or more connecting wires, mesh, foam, grid, perforated paper, screen, plastic screen, fiber screen, cloth, and polymer screen. In one embodiment of the invention, the screen may have approximately 10 filaments per millimeter. In another embodiment of the invention, the screen may have approximately 20 filaments per millimeter. In an additional embodiment of the invention, the screen may have approximately 30 filaments per millimeter. In an alternative embodiment of the invention, the screen may have approximately 100 filaments per millimeter. When designing the number of filaments per millimeter, approximately 20 percent (20%) is indicated.

[0082] The “bottom layer” is polymer, metal and / or plastic.

[0083] A “pulse generator” is a device such as a valve, pressure regulator or voltage-controlled pulse generator that is suitable for generating short (approximately 0.1 seconds, where approximately means adding or subtracting ten percent (10)) pulses of carrier gas.

[0084] "Carrier gas" is a gas that can generate excited matter under atmospheric pressure when there is an electrical discharge.

[0085] A “grid” is a sublayer in which gaps, spaces, or holes have been perforated or otherwise introduced into the sublayer, or in which windows or sections have been cut off or otherwise removed from the sublayer and a mesh has been inserted into the removed windows or sections. In embodiments of the invention, the thickness of the grid can be between a lower limit of about 1 micrometer and an upper limit of about 1 centimeter. Within this range, “approximately” means plus or minus twenty percent (20).

[0086] The phrase “background chemical substances” refers to “matrix molecules” and / or “introduced contaminants”.

[0087] The phrase “target molecule” or “analyte” refers to any naturally occurring substance (e.g., caffeine, cocaine, tetrahydrocannabinol) or a synthetic molecule that has been introduced into a biological system, such as drugs (e.g., lidocaine, methadone, sildenafil, lipitor, enalapril and their derivatives) and recreational drugs (e.g., morphine, heroin, methamphetamine and their derivatives).

[0088] Shorter than "introduced contaminants," these refer to chemical substances that become associated with the sample during sample preparation and / or sample analysis. Introduced contaminants can be airborne or present in or on surfaces that come into contact with the sample. For example, perfumes and deodorants can be associated with and analyzed during sample analysis. Alternatively, phthalates present in the plastic tubing used to handle the sample can leach from the tubing into the sample and thus be introduced into the sample.

[0089] The phrase “background chemical substances” refers to “matrix molecules” and / or “introduced contaminants”.

[0090] The phrase "ion inhibitor molecule" refers to a background chemical substance that inhibits the ionization of a target molecule and / or generates a background substance (which ionizes and impairs the detection of the target molecule).

[0091] The phrase "background ions" or "background material" refers to ions formed by background chemicals. Background material can include molecules themselves, molecular adducts, molecular fragments, or combinations thereof.

[0092] The term "matrix effect" refers to the reduction in the ionization of target molecules due to the presence of background substances. The matrix effect occurs when background chemicals inhibit the ionization of target molecules and / or when background substances themselves ionize and impair the target molecule. To avoid being bound by theory, in the former case, it is believed that the target molecule will not be ionized by the presence of background chemicals. In the latter case, the resulting mass spectrum is dominated by background substances, thus impairing the analysis of the target molecule. Background substances can inhibit and / or mask the ionization of target molecules.

[0093] The phrase “analytical volume” refers to an equal portion of the sample being analyzed, such as an equal portion of a sample used in a mesh for analysis.

[0094] The phrase "ion enhancer" refers to a chemical substance that inhibits matrix effects.

[0095] The term "peak abundance" refers to the number of ions produced. The peak abundance of the protonated molecular ion of a sample is a measure of the number of complete ions produced in the sample (other processes such as cationization can also be measures of the number of complete ions produced in the sample). The relative peak abundance of two substances is the sum of the intensities corresponding to each substance.

[0096] DART API CIE

[0097] The DART API CIE is an analytical method introduced using, for example, QuickStrip, and involves presenting a series of samples deposited at discrete locations on a movable surface. This surface is mounted on a holder fixed to linear guides, which allow constant linear movement (i.e., a fixed speed) to present the samples as a series for analysis. The surface (typically a mesh) contains regions where samples are present and regions where samples are not present. This linear movement results in the presentation of the samples in front of a static source of ionized material, and thus allows for scanning (and analysis) of the samples.

[0098] DART API CIE utilizes a carrier gas (e.g., a 1536 QuickStrip network card) to generate ionized material that is directed toward the surface. In DART API CIE operating mode, the carrier gas is not pulsed, and therefore the ionized material is directed toward the surface regardless of whether the sample is presented to it. Consequently, valuable purified carrier gas is wasted (see [link to DART API CIE operating mode]). Figure 3 ).

[0099] Furthermore, in the DART API CIE mode, background material is generated when no sample is present on the surface. Unwilling to be bound by theory, it is believed that when ionized material interacts with the leading (or trailing) edge of the sample, the analyte in the sample competes with the background chemical for the charge generated by the ionized material. If the analyte wins this competition, analyte ions are formed. If the background chemical wins the competition, background material is formed. Unwilling to be bound by theory, it is believed that this competition is not only won by either material but also driven by proton affinity in the positive ionization mode. Unwilling to be bound by theory, it is also believed that the formation of a large amount of background material before the leading edge can impair the detection of analyte material formed at the leading edge.

[0100] The advantage of the DART API CIE method lies in its ability to allow for imprecise (or non-reproducible) deposition of the sample being analyzed, as long as the sample is present somewhere within the area sprayed with ionized gas. In the DART API CIE method, the continuous spraying of ionized material results in the generation of ions from both the sample and the background during the experiment.

[0101] DART API PE

[0102] DART API PE is an analytical method that seeks to minimize carrier gas waste by utilizing robotic precision sample deposition and similarly precise presentation of the sample in front of a source that provides a spray of ionized material. By shutting off the carrier gas entering the source while simultaneously moving the sample into place, the ionized material formed by the source is preserved. Not to be bound by theory, it is believed that discharge continues when the carrier gas is shut off, but the ionized material leaving the source decays in the absence of carrier gas flow. A significant reduction in carrier gas consumption can be observed depending on the sample interval and the time required for sample desorption (see [link to relevant documentation]). Figure 3 In other words, by utilizing precise deposition and timing of the sample, it is unnecessary to address inaccurate (or unreproducible) deposition of the sample. Therefore, by utilizing precise deposition and positioning of ionized material, it is unnecessary to use a wide beam of ionized material. Instead, a narrow-end cap can be used to generate a confined spray of ionized material with a narrower spray pattern (i.e., a smaller range of effect).

[0103] To avoid being bound by theory, it is believed that by presenting a static sample, background material can only be observed when it successfully competes for charge with the analyte present in the sample. Changes in the analyte ion strength can be attributed to either the background material or the depletion of the analyte material due to the interaction between the ionized material and the sample. In embodiments of the invention, analyte ionization is optimized using a DART API PE operating mode with duration pulses of 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 seconds. In embodiments of the invention, analyte ionization is optimized using a DART API PE operating mode with a one (1) second pulse. In embodiments of the invention, analyte ionization is optimized using a DART API PE operating mode with two (2) second pulses.

[0104] DART API HE

[0105] DART API HE is an analytical method that seeks to minimize carrier gas waste while retaining the characteristics of DART APICIE. That is, by turning off the carrier gas and simultaneously localizing the ionized material in the sample region, a similarly significant reduction in carrier gas consumption was observed (see [link to DART APICIE]). Figure 3 The mixing speed is 3 mm / s.

[0106] carrier gas

[0107] In the presence of a carrier gas, DART API generates plasma around the discharge. Reducing the carrier gas pressure from approximately 70 psi to approximately 0 psi between approximately one (1) second and approximately three (3) seconds does not adversely affect the stability of the plasma. Within this pressure range, approximately refers to an increase or decrease of twenty percent (20). Within this time range, approximately refers to an increase or decrease of twenty percent (20). It is not desirable to be bound by theory, but it is believed that the plasma around the electrode remains in the region close to the stable plasma. In the absence of a carrier gas being introduced into the plasma, ionized material does not flow from the plasma to the sample. The generation of the carrier gas pulse is achieved by increasing the pressure of the carrier gas applied to the region close to the stable plasma, which forces ionized material to flow from the stable plasma generation region to the sample.

[0108] Helium DART

[0109] DART is another API method suitable for analyte analysis. Various embodiments of the DART API are described in U.S. Patent No. 7,112,785 to Laramee (hereinafter referred to as the '785 Patent), which is expressly incorporated herein by reference in its entirety and for all purposes. The '785 Patent relates to the desorption of ionized molecules from surfaces, liquids, and vapors using a carrier gas containing an active substance (RS). The DART API can use large-volume carrier gases; for example, helium is suitable, although other inert gases that can generate RS can also be used.

[0110] Nitrogen DART

[0111] APIs can ionize analyte molecules without using solvents to dissolve the analyte. Ionization occurs directly from solids and liquids. Molecules present in the gas phase can also be ionized by the active material leaving the API. In embodiments of the invention, the active material utilized can be excited nitrogen atoms or molecules. In embodiments of the invention, the active material can generate a long-lived metastable substance to affect analyte molecules at atmospheric pressure and, for example, to affect ionization. See also U.S. Patent Application No. 16,422,339, filed May 24, 2019, entitled “Apparatus and Method for Reducing Matrix Effects” by inventor Brian D. Musselman, which is incorporated herein by reference in its entirety and for all purposes.

[0112] Gas-ion separator (GIS)

[0113] In various embodiments of the invention, apparatus and methods for transferring analyte ions desorbed from the surface of an adsorbent using an atmospheric analyzer to the inlet of a mass spectrometer can utilize GIS. Embodiments of the invention include apparatus and methods for collecting and transferring analyte ions and / or other analyte substances formed within a support to the inlet of a mass spectrometer.

[0114] In embodiments of the present invention, one or both of the inlet and outlet GIS pipes may be made of one or more materials selected from the group consisting of: stainless steel, non-magnetic stainless steel, steel, titanium, metals, flexible metals, ceramics, quartz glass, plastics, and flexible plastics. In embodiments of the present invention, the length of the GIS pipe may range from 10 millimeters to 10 meters. In embodiments of the present invention, the GIS pipe may be made of a nonwoven material. In embodiments of the present invention, the GIS pipe may be made of one or more woven materials.

[0115] In various embodiments of the invention, a GIS comprising two or more coaxial tubes is used to allow sampling of large volumes of carrier gas, wherein gaps exist between the tubes and a vacuum is applied in the gap regions. In various embodiments of the invention, the GIS consists of an inlet tube and an outlet tube. In embodiments of the invention, the proximal end of the inlet tube is closest to the adsorbent surface, and the distal end of the inlet tube may be located at a distance from the proximal end where a vacuum can be applied. In various embodiments of the invention, the proximal end of the outlet tube is adjacent to the distal end of the inlet tube, and the distal end of the outlet tube enters the spectral system.

[0116] Ninety Degrees GIS

[0117] The use of robotic sample deposition allows the system to deposit submicroliter volumes of sample with precise, high-speed XY plate orientation for DART API analysis. Previously, the performance of the 90° GIS component was compromised by high background and matrix effects. Surprisingly, using a pulsed carrier gas source and stepping to a fixed position, the 90° GIS showed no signs of high background and matrix effects. Therefore, the pulsed carrier gas source and stepping to a fixed position allow for direct DART API analysis using the 90° GIS from higher-performance robotic technology, without needing to move the sample from the sample deposition robot. Furthermore, the 90° GIS can be combined with an extended XY plate with a retainer that allows the sample deposited on the QuickStrip mesh to move through a desorption / ionization region located at the distal end of the DART source, such that the sample deposited on the front side of the mesh can be vaporized and ionized near the proximal end of the GIS located on the rear side of the mesh. The 90-degree GIS can be combined with an extended XY plate with a retainer that allows samples deposited on the QuickStrip net to move through a desorption and ionization region located at the distal end of the DART source, such that samples deposited on the front side of the net can be vaporized and ionized near the proximal end of the GIS located on the rear side of the net.

[0118] Figure 15A This is a line drawing of a pipetting robot (1504) with a series of 16 positive displacement pipettes (1523) for delivering small volumes of samples onto the surface of a QuickStrip-96 wire mesh consumable (1532) mounted on its sampling stage (1543), as shown. Figure 16A As shown. Once the samples have been pipetted to their precise locations, the sampling stage is moved to a robotic arm designed to move the samples through the ionization region of the DART API source to ionize the samples in PE mode. Figure 15B This is a line drawing of the DART API source installed in a vertical position (110), where the 2.5mm outlet cap (118) is installed in a straight line with the 90-degree GIS (140) (which is connected to the MS (170) instrument), as shown. Figure 16B As shown. Attempts to perform 90-degree GIS experiments using the DART API CIE are sometimes unsuccessful. Not wanting to be bound by theory, it is believed that using the DART API CIE may generate background material, and due to the 90-degree GIS configuration, this background material is not removed from the ionized region as rapidly as in a linear configuration, thus increasing competition between the background material and the analyte.

[0119] Figure 16AIt is a pipetting tip for the TTP Labtech Mosquito robot (1504), which has a series of 16 positive displacement pipettes (1523) to deliver small volume samples onto the surface of a QuickStrip-96 wire mesh consumable (1532) mounted on its sampling stage (1543). Figure 16B It is a DART API source installed in a vertical position, with the 2.5mm exit cap aligned with the GIS interface connected to the quality detector at a 90-degree angle. Figure 16C It is a DART API source installed in a vertical position, with the 2.5mm exit cap aligned with the GIS interface connected to the quality detector at a 90-degree angle. Figure 16D It is a DART API source installed in a vertical position, in which the 2.5mm outlet cap is aligned with the smooth, continuous tube surface GIS interface connected to the quality detector at a 90-degree angle.

[0120] Utilizing a DART API PE with a 90° GIS configuration enables the generation of analyte ions with higher efficiency than the DART API CIE, where pulse timing of ionization occurs only in the presence of the sample, reducing the generation of background substances. Due to the reduced presence of background substances, the likelihood of intermolecular interactions is decreased. As a result, analyte substances can pass through the 90° GIS more efficiently with fewer intermolecular interactions.

[0121] Ninety Degrees GIS utilizes the DART API PE to facilitate rapid and reproducible desorption and analysis of fentanyl, where all analyte ion species present in the sample are detected. This is also the case for ultra-low volume samples (200 nL), where sample deposition and the sample's position before ionization are controlled by a precise robotic system. Therefore, the DART API PE with its extended XY plate holder enables direct DART ionization at the front of the plate. Not wanting to be bound by theory, it is believed that the use of pulsed carrier gas to generate fewer ions in absolute numbers reduces the likelihood of intermolecular ion-ion interactions and thus facilitates more efficient passage through the elbow tube.

[0122] Hat size

[0123] The spot size of the ionized material affecting the grid can vary depending on the distance between the source of the ionized material and the grid. A cap with a vent can be used to limit the spot size at the sample through which the ionized material diffuses. The size of the cap and the vent can be selected to adjust the spot size of the ionized material at the sample. The cap (117, 118) can extend a certain distance (121) between a lower limit of about 0.1 mm and an upper limit of about 5.0 mm (e.g., 0.2, 0.3, 0.4, etc. up to 4.5, 4.6, 4.7, 4.8, 4.9 mm), where about refers to adding or subtracting twenty percent (20) within this range. In various embodiments of the invention, the distance (121) can be continuously adjustable to optimize the scan rate based on several factors, including, for example, the number of samples to be analyzed. The vent (119) can have various shapes, including oval, elliptical, rectangular, square, and circular. The circular cap aperture (119) may have a diameter between a lower limit of about 0.1 mm and an upper limit of about 5.0 mm (e.g., 0.2, 0.3, 0.4, etc. up to 4.5, 4.6, 4.7, 4.8, 4.9 mm), where "about" refers to plus or minus twenty percent (20). For non-circular cap apertures (119), the maximum range of the opening in the cap aperture may be between a lower limit of about 0.1 mm and an upper limit of about 5.0 mm (e.g., 0.2, 0.3, 0.4, etc. up to 4.5, 4.6, 4.7, 4.8, 4.9 mm), where "about" refers to the spatial resolution plus or minus twenty percent (20). In various embodiments of the invention, the cap aperture (119) may be continuously adjustable to optimize spot size and spatial resolution, thereby allowing selection of appropriate carrier gas pulses and / or scan rates to optimize sensitivity and minimize the generation of background material, contamination, or artifacts.

[0124] In embodiments of the present invention, such as Figure 2A As shown, for a narrow cap (117) with a 1.0 mm diameter orifice (119), the distance (121) between the distal end of the DART source (115) and the sample (130) is approximately 2.0 mm. This configuration (the narrow cap with a 1.0 mm diameter orifice and 2.0 mm from the sample) will be referred to as the “1.0 mm exit cap”. Using the 1.0 mm exit cap configuration, spots spaced 2.25 mm apart (i.e., the distance from neighboring samples) can be analyzed. Typically, a 200 nL sample is dried to a spot diameter of approximately 1.1 mm, resulting in spots spaced approximately 1.1 mm apart. In this configuration, using a DART API CIE with a scan rate of 2.5 mm / s, the observed contribution of material from neighboring samples is minimal (i.e., minimal cross-contamination). Therefore, in an embodiment of the invention, the spatial resolution of 2.5 mm / s is approximately 1 mm. Within this range, approximately refers to plus or minus twenty percent (20).

[0125] In an alternative embodiment of the invention, Figure 2B The diagram shows a longer cap (118) with an approximately 2.5 mm diameter hole (119) and a distance (121) of approximately 1.0 mm between the distal end of the DART source (115) and the sample (130). This configuration (the longer cap with a 2.5 mm diameter hole and a distance of 1.0 mm from the sample) will be referred to as the “2.5 mm exit cap”.

[0126] 1536 samples

[0127] In embodiments of the present invention, such as Figures 13A-13D and Figures 14A-14E As shown, using a DARTAPI PE with a 2.5mm outlet cap, it is possible to analyze spots formed by applying 200 nL of xxx sample aliquots spaced 2.25 mm (x-direction) and 2.25 mm (y-direction) apart (i.e., distance from neighboring samples) without observing any material from neighboring samples (i.e., no cross-contamination). Therefore, in embodiments of the invention, the spatial resolution is approximately 1 mm. Within this range, approximately refers to plus or minus twenty percent (20).

[0128] Figure 13A The caffeine (SIM 195.1 ± 0.5 Da) present in a 200 nL volume mixture of cocaine (1 mg / mL), lidocaine (1 mg / mL), and methadone (1 mg / mL) was analyzed by DART API PE (with a 2.5 mm exit cap) mass spectrometry on a net sample presented in 1536 template format. Figure 13B Lidocaine (SIM 235.2 ± 0.5 Da) present in a 200 nL volume mixture of caffeine (1 mg / mL), cocaine (1 mg / mL), and methadone (1 mg / mL) was analyzed by DARTAPI PE (with a 2.5 mm exit cap) mass spectrometry on a net sample presented in 1536 template format. Figure 13C Cocaine (SIM 304.3 ± 0.5 Da) present in a 200 nL volume mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL), and methadone (1 mg / mL) was analyzed by DART API PE (with a 2.5 mm exit cap) mass spectrometry on a net sample presented in 1536 template format. Figure 13DMethadone (SIM 310.2 ± 0.5 Da) present in a 200 nL volume mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL), and cocaine (1 mg / mL) was analyzed by DART API PE (with a 2.5 mm exit cap) mass spectrometry on a net sample presented in 1536 template format.

[0129] Figure 14A The caffeine (SIM 195.1 ± 0.5 Da) present in a mixture of cocaine (1 mg / mL), lidocaine (1 mg / mL) and methadone (1 mg / mL) in a 200 nL volume was subjected to DART API PE (with a 2.5 mm exit cap) mass chromatography on a net (twelve (12) replicate positions from position 1 to 12) of a sample presented in 1536 template format. Figure 14B Lidocaine (SIM 235.2 ± 0.5 Da) present in a mixture of caffeine (1 mg / mL), cocaine (1 mg / mL) and methadone (1 mg / mL) in a 200 nL volume was subjected to DART API PE (with a 2.5 mm exit cap) mass chromatography on a sample presented in a 1536 template format (twelve (12) replicate positions from position 1 to 12). Figure 14C Cocaine (SIM 304.3 ± 0.5 Da) present in a mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL) and methadone (1 mg / mL) in a 200 nL volume was subjected to DART API PE (with a 2.5 mm exit cap) mass chromatography on a sample presented in a 1536 template format (twelve (12) replicate positions from position 1 to 12). Figure 14D Methadone (SIM310.2±0.5Da) present in a mixture of caffeine (1 mg / mL), lidocaine (1 mg / mL) and cocaine (1 mg / mL) in 200 nL volume was subjected to DART API PE (with a 2.5 mm outlet cap) mass chromatography on a net (twelve (12) replicate positions from position 1 to 12) of a sample presented in 1536 template format. Figure 14E The samples were methadone (1 mg / mL), caffeine (1 mg / mL), lidocaine (1 mg / mL) and cocaine (1 mg / mL) on a DART API PE (with a 2.5 mm outlet cap) TIC, which were applied to a net (twelve (12) repeating positions from position 1 to 12) of samples presented in 1536 template format.

[0130] API

[0131] The API process involves the initial action of ionizing a gas through discharge. In plasma-based APIs, the discharge of inert gases such as nitrogen, argon, and helium leads to the formation of ionized gas molecules, atoms, and metastable molecules and atoms. These charged and high-energy particles leave the ionization source, where they interact with molecules in the air, including background chemicals. Ions are formed during this interaction. These ions are typically (i) fully protonated or deprotonated molecules, such as NO. + O2 - H3O + (ii) clusters of water molecules with one proton, and (iii) ions derived from molecules present in ambient air (including background chemicals). APIs become analytical tools when those protonated water molecules interact with the analyte present in the air, resulting in proton transfer to the analyte. Analytes can be introduced into ionized substances as gases, liquids, or solids located in the path of gas discharge products. Two forms of APIs are Atmospheric Pressure Chemical Ionization (APCI) and Direct Real-Time Analysis (DART). APCI uses a discharge between a high-pressure needle and the surface where the sample is applied, while DART uses a discharge and a heated gas to desorb the sample from the surface into the atmosphere (DARTAPI). In the absence of a sample, molecules present in ambient air are ionized and, when detected, generate a mass spectrum.

[0132] In many cases, intentionally introducing a sample into an ionized substance can lead to the formation of ions that are easily measured using a spectrometer located near the API site.

[0133] In biological samples, certain molecules possess very high proton affinity, meaning that intentionally introducing them into ionized material will cause them to ionize and form ionized dimers containing two molecules and one proton. High proton affinity molecules can also combine with another molecule or a group of closely related molecules to form protonated mixed dimers or tetramers. The proton affinity of these molecules makes ionization methods impossible for analysis because other target molecules in the sample cannot remain unionized and therefore cannot be detected using spectrometers located near the API site. In API experiments, the dominance of a single molecule or group of high proton affinity molecules in the resulting spectrum is typically considered an experiment with matrix effects.

[0134] In theory, during ambient ionization, when the sample being analyzed contains background substances that ionize more efficiently than the analyte, the target analyte or molecule cannot be detected. As the characteristics of the background chemicals become more competitive, the detection of the target molecule is impaired. Not wanting to be bound by theory, it is believed that as the affinity of background chemicals for ionized substances increases, the detection of the target molecule is impaired, thus reducing the detection efficiency of the target molecule. This is a manifestation of the "matrix effect," a condition in APIs that can prevent the use of this method for analysis. In specific environments, multiple background chemicals can cause the matrix effect. For example, the presence of urea in urine and nicotinamide in tobacco products are examples where the background chemicals dominate the resulting spectrum to the point that they make it impossible to reliably detect other chemicals in the sample.

[0135] In embodiments of the invention, the amount of ionized material generated can be increased by changing from a 1.0 mm outlet cap to a 2.5 mm outlet cap. Similarly, the amount of ionized material generated can be increased by changing from DART API HE or DART API PE to DART API CIE. Unexpectedly, it was observed that using DART API PE with a 2.5 mm outlet cap improved sensitivity compared to using DART API CIE with a 2.5 mm outlet cap. Not wishing to be bound by theory, it is believed that the reduced ionized material due to the use of DART API PE results in a narrower time packet of ionized material, which allows for a reduced competition time between the analyte and background material, leading to increased analyte ion formation. This necessitates a wider orifice and a shorter distance to the sample, suggesting that the reduced ionized material can be offset, and that a wider orifice and / or a shorter distance facilitates directing more ionized material packets toward the sample.

[0136] Figure 2A and 2BAn API source (110) is shown, in which ionized material exits the source through caps (117, 118) at the distal end and interacts with molecules present in the ambient atmosphere, resulting in the generation of ions. Ions and a neutral gas are drawn from an ionized region (120) surrounding a sample applied to a surface (130) into a spectrometer (170) by a vacuum applied to the proximal end of a transfer tube (140), which is applied to the distal end (150) of the transfer tube (140) by either the spectrometer (170) or an external vacuum pump (180). In an embodiment of the invention, the ion-containing gas enters a gas ion separator at the proximal end of the transfer tube (140) and travels toward the inlet region (160) containing the spectrometer inlet tube (165), where it is drawn into the spectrometer (170) by a vacuum of the spectrometer (170) or a combination of that vacuum and a vacuum from an external pump (180). The volume of ion-containing gas entering the spectrometer (170) through the spectrometer inlet tube (165) can be analyzed to allow for ion detection and characterization. Mass spectra generated by a sample-bearing mesh are dominated by ions generated from low-mass molecules present in the atmosphere and persistent organic molecules produced from plastics and other chemicals. In experimental testing, sample introduction involves guiding the target gas or positioning the target sample on a surface (130), which is then positioned in the ionization region (120) between the source (110) and the spectrometer (170), and the surface (130) typically causes an immediate change in the spectral appearance.

[0137] Example 1

[0138] use A robot (TTP Labtech, Cambridge, UK) deposited eight (8) samples into a first-stage 12 (12) well using a 12-well format. The sample (a mixture of 200 nml of cocaine (0.01 mg / mL), fentanyl (0.01 mg / mL), and codeine (0.01 mg / mL)) was deposited on a wire mesh sieve (IonSense, Saugus, Massachusetts). Figure 1 Positions 3, 4, 5, 6, 7, 8, 9, and 10 are indicated. Prepare the first QuickStrip (90). Insert the linear guide (20) holding the sample card (40) into the blank (30) and set it to scan at a speed of 3 mm / s. Figure 1 For each of the twelve (12) indicated analytical points (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), a laser-cut stainless steel mesh (50) is placed in the sample card (40).

[0139] The first QuickStrip (90) was analyzed using the DART API source, with helium as the ionizing agent and the temperature set to 300°C to generate precursor ions for the abused drug. Figure 4A It is a positive DART API CIE (1.0 mm outlet cap) mass chromatogram of fentanyl (SIM 337.2±0.5 Da). Figure 4B It is a positive DART API CIE (1.0mm exit cap) mass chromatogram of cocaine (SIM 304.3±0.5Da). Figure 4C It is a positive DART API CIE (1.0mm outlet cap) quality chromatogram of codeine (SIM 300.3±0.5Da). Figure 4D The positive traces of the formed ions are DART API CIE (1.0 mm exit cap) TIC traces. At the analysis points where no sample was applied (1, 2, 11, and 12, see...). Figure 1 Significant TIC was observed in the study, indicating that the ionization of molecules present in the environment (e.g., including phthalates and perfluoroalkanes) can generate a relatively rich pool of background matter, which may reduce the efficiency of the ionization process of the target molecules once the sample is introduced into the ionization region. Figure 10 As shown, Figure 4A (short dash) Figure 4B (long underline) Figure 4C The width of the peak in the mass chromatogram (with dotted lines) and Figure 4D The comparison of the widths of the TIC peaks in the solid line shows... Figure 4D peak ratio in Figures 4A to 4C The observed peaks are broader. Furthermore, the intensity of the TIC trace is greater than... Figures 4A to 4C The SIM in the sample increases at an earlier time. Without being bound by any theory, it is believed that short time intervals for the formation of “irrelevant ions” (i.e., ions formed by background chemicals unrelated to the sample) have been observed, which contribute to the TIC trace. Therefore, it is proposed that those background chemicals that form irrelevant ions exist and that they can interact with or compete with the sample for ionization. Thus, reducing the ability of background chemicals to compete with the sample would improve the sensitivity of sample analysis.

[0140] Example 2

[0141] The same sample as in Example 1 was deposited on a second QuickStrip using a Mosquito robot.

[0142] Then analyze the second QuickStrip using the DART API source as in Example 1, but with a 2.5mm exit cap.

[0143] Figure 5A It is a positive DART API CIE (2.5mm outlet cap) mass chromatogram of fentanyl (SIM 337.2±0.5Da). Figure 5B It is a positive DART API CIE (2.5mm exit cap) mass chromatogram of cocaine (SIM 304.3±0.5Da). Figure 5C It is a positive DART API CIE (2.5mm outlet cap) mass chromatogram of codeine (SIM 300.3±0.5Da). Figure 5D The positive DART API CIE (2.5mm exit cap) TIC traces of all ions generated from the mesh are a function of the sample position on the mesh. TIC (obtained using a 1.0mm exit cap) Figure 4D ) and TIC obtained using a 2.5mm exit cap ( Figure 5D Comparison confirms that the ionization region increases with increasing cap size. The increased volume of gas leaving the cap leads to a near-constant generation of ions from both the background and the sample, meaning that a large number of background-related ions exist in the ionization region before the sample is ionized. This is despite the physical barrier imposed by the metal teeth present at each of the individual locations (see [link to article]). Figure 1 The blanks at positions 1 to 12 (30) show relatively constant ion generation, but the generation of ions remains almost constant. A narrow cap was observed to provide more efficient ion generation for analysis, but it does not restrict the generation of background material and therefore does not reduce competition between background material and sample-related ions. Figures 5A to 5C The peak width in the mass chromatogram is related to TIC ( Figure 5D The comparison of peak widths in the samples again shows that there is a nearly continuous time period before the analysis of each sample in which ions unrelated to the sample are present, and therefore in which those background chemicals are present and are able to interact with or compete with the ionized substances.

[0144] Example 3

[0145] The same sample as in Example 1 was deposited on a third QuickStrip using a Mosquito robot.

[0146] Then, the third QuickStrip was analyzed using the DART API source as operated in Example 1, where the sample was presented discontinuously in the DARTAPI HE, where the ionized substance was turned off before the first sample was presented, turned on when the sample was presented and moved at 3 mm / s for one (1) second, and then interrupted until the second sample was presented for analysis, where the pulsed gas and moving process was repeated for all twelve (12) samples.

[0147] Figure 6AIt is a positive DART API HE (1.0mm outlet cap) mass chromatogram of fentanyl (SIM 337.2±0.5Da). Figure 6B It is a positive DART API HE (1.0mm outlet cap) mass chromatogram of cocaine (SIM 304.3±0.5Da). Figure 6C It is a positive DART API HE (1.0mm outlet cap) mass chromatogram of codeine (SIM 300.3±0.5Da). Figure 6D This is the positive TIC trace of all formed ions in the DARTAPI HE (1.0 mm exit cap) source. When analyzing samples, it is assumed that the more sample present, the greater the observed signal intensity. Furthermore, it is thought that more sample ions can be desorbed by moving the sample through the ionizing material as a function of time, thus exposing more sample to ionization conditions. Both of these assumptions are challenged by the presented results. In the DARTAPI HE (1.0 mm exit cap), sample movement occurs with the ionizing material pressure turned off until the mesh's position relative to the source allows the ionizing material to be directed toward the sample. The activation time of the carrier gas pressure in the ionization source and the mesh movement to present the sample is very short. Figure 6A , 6B The peak width in the mass chromatography of 6C is related to TIC ( Figure 6D A comparison of the peak widths in the samples showed that no background chemical-related ions were present before the sample was introduced (see [reference]). Figure 11A-11B In other words, there is no nearly continuous period of time before the sample analysis period, during which ions unrelated to the sample are present. (Check) Figure 5A , 5B 5C and TIC ( Figure 5D The shape of peaks in mass chromatography shows the presence of ions unrelated to the sample as it moves. For example, the observed tailing of each peak indicates that sample ions are competing with background chemical molecules for ionization.

[0148] Example 4

[0149] The same sample as in Example 1 was deposited on the fourth QuickStrip using the Mosquito robot.

[0150] Then analyze the fourth QuickStrip using the DART API source as described in Example 3, but with a 2.5mm exit cap.

[0151] Figure 7A It is a positive DART API HE (2.5mm outlet cap) mass chromatogram of fentanyl (SIM 337.2±0.5Da). Figure 7BIt is a positive DART API HE (2.5mm exit cap) mass chromatogram of cocaine (SIM 304.3±0.5Da). Figure 7C It is a positive DART API HE (2.5mm outlet cap) mass chromatogram of codeine (SIM 300.3±0.5Da). Figure 7D The positive DART API HE (2.5mm exit cap) TIC traces of all ions formed from the mesh are a function of the sample position on the mesh. TIC (obtained using a 1.0mm exit cap) Figure 6D ) and TIC obtained using a 2.5mm exit cap ( Figure 7D Comparisons confirmed that the ionization region increases with increasing cap size. In embodiments of the invention, the absence of ions before increasing pressure to force the ionized material to flow at the mesh resulted in preferential generation of sample-related ions. It was observed that the sample moved into the ionization region before the time it took to increase pressure to direct the ionized material toward the sample, thus improving the generation of sample-related ions. The observations of increased peak width and increased tailing of each mid-peak in mass chromatography relative to CIE indicate that background-related ions are being generated and that these ions are reducing the generation of sample-related ions.

[0152] Example 5

[0153] The same sample as in Example 1 was deposited on the fourth QuickStrip using the Mosquito robot.

[0154] Then, using the DART API source as operated in Example 1 (i.e., with a 1.0mm exit cap but using DART API PE), analyze the fifth QuickStrip (i.e., set the linear guide to jump to, as in Example 1). Figure 1 Each of the twelve (12) analysis points indicated (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12) is paused for one (1) second after each jump, during which helium is pulsed into the DART API source.

[0155] Figure 8A It is a positive DART API PE (1.0 mm outlet cap) mass chromatogram of fentanyl (SIM 337.2±0.5 Da). Figure 8B It is a positive DART API PE (1.0mm export cap) mass chromatogram of cocaine (SIM 304.3±0.5Da). Figure 8C It is a positive DART API PE (1.0mm outlet cap) mass chromatogram of codeine (SIM 300.3±0.5Da). Figure 8DThe positive DART API PE (1.0 mm outlet cap) TIC trace of the formed ions. In embodiments of the invention, the amount of desorbed sample is increased by moving the sample into place, increasing the pressure applied to the carrier gas for a short interval, and then shutting off the carrier gas pressure. It is not desirable to be bound by theory; it is believed that ionization increases when a carrier gas pulse is applied. Figures 8A to 8C The peak width in the mass chromatogram is related to TIC ( Figure 8D A comparison of peak widths in the data shows that no background-related ions were present before the pressure reduction and only briefly afterward. There were no nearly continuous periods of time before the sample analysis period during which sample-irrelevant ions were generated, and ion generation was temporally limited by the reduction in ionized mass flux, effectively minimizing the formation of background substances and sample-related ions. [Check] Figures 8A to 8C and TIC ( Figure 8D The peak shapes in the mass chromatography showed a rapid increase in the generation of sample-related ions, and the use of a pulsed gas method compared to a stationary sample reduced the likelihood of peak tailing. No background substances (such as TICs) were present. Figure 8D The fact that the line in the curve returns to the baseline indicates that makes it possible to use less complex peak detection algorithms, which have previously been shown to be difficult to do due to signals with non-uniform peak shapes.

[0156] Example 6

[0157] The same sample as in Example 1 was deposited on the sixth QuickStrip using the Mosquito robot.

[0158] Then analyze the sixth QuickStrip using the DART API source as described in Example 5, but with a 2.5mm exit cap.

[0159] Figure 9A The mass chromatogram of fentanyl (SIM 337.2±0.5Da) on DART API PE (2.5mm outlet cap) is shown. Figure 9B It is a positive DART API PE (2.5mm outlet cap) mass chromatogram of cocaine (SIM 304.3±0.5Da). Figure 9C It is a positive DART API PE (2.5mm outlet cap) mass chromatogram of codeine (SIM 300.3±0.5Da). Figure 9D The TIC traces are positive DART API PE (2.5mm exit cap) traces of the formed ions. TIC traces were obtained using a 1.0mm exit cap. Figure 8D ) and TIC obtained using a 2.5mm exit cap ( Figure 9DComparison confirmed that although the ionization region increased when using the 2.5 mm outlet cap (compared to the 1.0 mm outlet cap), the generation of background material in the DART API PE (2.5 mm outlet cap) did not increase compared to the DART API PE (1.0 mm outlet cap). In embodiments of the invention, the absence of ions before increasing the pressure to force the ionized material to flow at the mesh resulted in the preferential generation of sample-related ions. Sample movement into place (followed by a short-term introduction of carrier gas with increasing carrier gas pressure) resulted in the preferential generation of sample-related ions. DART API PE (2.5 mm outlet cap) mass chromatography ( Figure 9A , 9B The peak width of 9C is narrow, and it is similar to that of DART API PE (1.0mm outlet cap) ( Figure 8A , 8B The peak widths observed in 8C are comparable. The reduction in peak tailing is significant, and the improvement in peak abundance is noteworthy, which differs from observations from continuous pulse sample movement experiments, where a 2.5 mm exit cap was observed to result in a more continuous generation of background material.

[0160] In an embodiment of the present invention, in mass chromatography ( Figure 9A , 9B The narrow and abundant peaks observed in (9C) facilitated peak analysis because peak detection was unnecessary. In mass chromatography (... Figure 9A , 9B The narrow and abundant peaks observed in mass chromatography (9C) do not require background subtraction to generate a numerical representation of the information contained in the mass chromatography. Figure 9A , 9B In mass chromatography (MCC), the ion current abundance can be summed over time to generate an average value, regardless of peak height. In this way, values ​​that can be obtained in mass chromatography (MCC) can be generated. Figure 9A , 9B The information contained in the mass chromatograms (t1, t2, t3, t4, t5, t6) is represented digitally. In this way, 384 samples of DART API PE (2.5 mm outlet cap) can be analyzed using two (2)-second pulse ionization (t1) and one (1)-second jump and delay (t2), thus requiring 3.4 seconds per sample for baseline separation peaks and a total of 22 minutes for 384 samples. The information contained in the 384 mass chromatograms can be stored in a single file and accessed using analytical software. In embodiments of the invention, using analytical software, the quantitative and qualitative information of the 384 samples stored in a single file can be determined. In embodiments of the invention, by generating mass chromatograms containing peaks that do not require processing such as peak detection or background subtraction and combining analysis and storage in a single file, the speed at which the storage file and stored information are opened is not limited by the sampling speed.

[0161] In an embodiment of the invention, the sample comprises two or more sample points, with a first sample point and a second sample point separated by a distance d. The two or more sample points are processed such that during the time t1 of a first pulse in the two or more pulses, one or more ionized substances are directed toward the first sample point, and during the time t1 of a second pulse in the two or more pulses, the one or more ionized substances are directed toward the second sample point. The two or more pulses are separated by a time t2, and the peak abundance corresponding to one or more sample ions detected by the spectrometer for the first sample point is detected between a lower limit of approximately 0.9t1 seconds and an upper limit of approximately 1.1t1 seconds, where peak abundance approximately refers to addition or subtraction of ten percent. In an alternative embodiment of the invention, the peak abundance corresponding to one or more sample ions detected by the spectrometer for the first sample point is detected between a lower limit of approximately 0.95t1 seconds and an upper limit of approximately 1.05t1 seconds. In embodiments of the invention, the relative peak abundance corresponding to background ions is between a lower limit of about 0.01 and an upper limit of about 0.1, compared to the peak abundance corresponding to sample ions detected by a spectrometer for sample points.

[0162] Example 7

[0163] By lowering the export cap Figure 2A-2B (119) The gas pressure on the proximal side is increased, and then that pressure is increased to establish the gas flow to the net, thus completing the gas pulse. The greater the carrier gas flow, the greater the transfer of ionized material to the net. To examine the effect of carrier gas flow (e.g., carrier gas volume) on the generation of target ions from the sample, the same volume of sample was exposed to ionized material leaving the 1.0 mm outlet cap compared to leaving the 2.5 mm outlet cap, where, when the pressure on the proximal side of the orifice is equal, the gas volume flowing through the outlet orifice is larger for the 2.5 mm outlet cap. Using the SIM of the analyte fentanyl in a 200 nL sample, when the gas leaves the 1.0 mm outlet cap ( Figure 4A ) and exit cap 2.5mm ( Figure 5A When comparing the relative abundance of protonated molecules, the comparison is significant because the relative abundance decreases significantly as more ionized material is directed toward the sample on the net. For cocaine ( Figure 4B )contrast( Figure 5B ) and codeine ( Figure 4C )contrast( Figure 5C Similar results were observed. The relative abundance of all ions produced in each analysis was examined using a 1.00 mm outlet cap. Figure 4D The TIC comparison generated using a 2.5mm export cap () Figure 5DThe TIC indications generated, while seemingly significant in relative abundance with a 1.0 mm outlet cap compared to a 2.5 mm outlet cap, show that the near-continuous generation and detection of ions with the 2.5 mm outlet cap results in a significantly larger volume of ions, which reduces the generation of analyte ions. It was observed that the ion continuum indication generated in the 2.5 mm outlet cap experiments was contributing to background material, and these ions were reducing the volume of ionized material available for generating detectable analytes.

[0164] The experiments described in Examples 5 through 7 illustrate the effect of background material on detection in the absence of pulse ionization and sample movement. The effect of the outlet cap on ion production in DART API HE was examined by checking the SIM of the analyte fentanyl in a 200 nL sample. A 1.0 mm outlet cap was used. Figure 6A The relative abundance of protonated molecules was compared using a 2.5mm exit cap. Figure 7A The comparison of the relative abundance of protonated molecules indicates that the effect of the exit cap is not as significant as the difference between DART API HE and DART API CIE (because the relative abundance of fentanyl-related ions is greater in DART API CIE with a 1.0 mm exit cap) (see Figure 5A For cocaine ( Figure 6B )contrast( Figure 7B ) and codeine ( Figure 6C )contrast( Figure 7C Similar results were observed. The relative abundance of all ions produced in each analysis was examined using a 1.0 mm outlet cap in the case of DART API PE. Figure 6D The TIC comparison generated using a 2.5mm export cap () Figure 7D The TICs produced by this method are more comparable because the relative abundance of ions is more comparable despite the larger gas flow to the net. In the case of DART API HE, the generation of ions from the analyte appears to be improved; however, the 2.5 mm outlet cap still seems to induce ionization of background material, so it is not ideal.

[0165] The experiments described in Examples 5 through 7 confirmed the influence of background on DART API HE detection. Under DART API PE experimental conditions, there are short time intervals during which the generated mass spectra are rich in sample-related ions, and then the sample-related ions decrease because the spot (where the sample has been applied to the net) is no longer located in the region being affected by ionized substances. In embodiments of the invention, the effect of the outlet cap on ion production in DART API PE was examined by checking the SIM of the analyte fentanyl in a 200 nL sample. When the gas leaves the 1.0 mm outlet cap ( Figure 8A ) and exit cap 2.5mm ( Figure 9AWhen compared, the comparison of the relative abundance of protonated molecules was significantly improved with the 2.5mm exit cap, as the significant increases and decreases in relative abundance and fentanyl SIM were improved compared to the 1.0mm exit cap. For cocaine ( Figure 8B )contrast( Figure 9B ) and codeine ( Figure 8C )contrast( Figure 9C Similar results were observed. Examining the relative abundance indicators of all ions produced in each analysis, in the DART API PE, the 2.5 mm outlet cap improved analyte detection. Using a 1.0 mm outlet cap ( Figure 8D The TIC indicator generated shows the ion abundance ratio using a 2.5mm outlet cap. Figure 9D The ion abundance produced is low; however, since the production of analyte ions is preferred over background substances, the use of a DART API PE with a 2.5 mm outlet cap is preferred.

[0166] In embodiments of the invention, DART API PE was observed to produce a more uniform peak, indicating less interference from background material. In embodiments of the invention, DART API PE and DART API HE reduced the likelihood that the sample would be completely removed from the target during analysis, thus limiting the possibility of background material ionization. In embodiments of the invention, sufficient gas flow for desorption and ionization of the sample was achieved by matching the device pressure and flow rate to the pulse duration to optimally desorb the sample within that duration without requiring longer. It is important to observe improved signal with different outlet caps because sample size may vary, potentially requiring ionization from a larger surface area. Flowing more ionized material through a 2.5 mm outlet cap results in a wider ionization field, such as DART API CIE (see DART API CIE). Figures 4A-4D and Figures 5A-5D As shown in the diagrams (DART APIHE), where TIC did not return to the baseline. A wider ionization field can produce improved results if the sample is applied with lower positional accuracy or distributed over a larger area. However, a wider ionization field is unnecessary due to the precise positioning accuracy and the application of small sample volumes. On the other hand, insufficient carrier gas flow is also likely to be avoided. That is, sufficient ionizing material is required to successfully ionize the sample.

[0167] A common premise for sample analysis is that the more sample present, the greater the signal intensity observed for that sample. Furthermore, from this premise, it follows that by moving the sample through an ionized substance as a function of time, the amount of desorbed sample ions can be increased so that all samples can be desorbed. Unexpected results allow us to question the basis of these two premises. These unexpected results demonstrate improved sensitivity observed through (i) precise localization of a sample with a reduced volume and (ii) precise localization of short pulses of ionized substance on the sample without moving the ionized substance relative to the sample. Examples considered herein also include the following examples R1 to R35, S1, and T1 to T50.

[0168] Example R1. A sampler for depositing a volume of biological sample for atmospheric ionization, comprising: a mesh designed to confine a sample region; a supply source capable of directing ionized material formed in the atmosphere toward the confined sample region; and a spectrometer for analyzing sample ions formed by said ionized material.

[0169] Example R2. The sampler according to Example R1, wherein the sample is one or more adsorbed, absorbed, bound, or contained in the network.

[0170] Example R3. The sampler according to Example R1 or R2 further includes means for positioning the net to interact with the ionized material.

[0171] Example R4. The sampler according to Examples R1 to R3, wherein the density of the diluted sample on the surface is between the following two: a lower limit of about 1 picogram per square millimeter; and an upper limit of about 1 nanogram per square millimeter.

[0172] Example R5. The sampler according to Examples R1 to R4, wherein the ionized material comprises ionized material dispersed in a gas.

[0173] Example R6. The sampler according to Examples R1 to R5 further includes a gas ion separator introduced after the ionized substance interacts with the diluted sample and before the sample ions enter the spectrometer.

[0174] Example R7. The sampler according to Examples R1 to R6, wherein the mesh is a grid.

[0175] Example R8. The sampler according to Examples R1 to R7 further includes means for moving the net relative to the ionized material.

[0176] Example R9. An ionizer for pulsed atmospheric ionization of a sample present in serum, comprising: a surface designed to confine a surface region; a robot programmed to receive a sample, programmed to generate a confined region sample, and programmed to deliver the sample to the confined region surface, wherein the sample density on the surface is less than about 1 nanogram per square millimeter; and a supply source capable of directing ionized material formed by a pulsed atmospheric ionization source toward the confined region sample on the surface.

[0177] Example R10. The ionizer according to Example R9, wherein the diluted sample is adsorbed, absorbed, bound, or contained on the surface of one or more.

[0178] Example R11. The ionizer according to Example R9 or R10 further includes means for positioning the surface to interact with the ionized material.

[0179] Example R12. The ionizer according to Examples R9 to R11, wherein the ionizing material comprises an ionizing material dispersed in a gas.

[0180] Example R13. The ionizer according to Examples R9 to R12 further includes a gas ion separator.

[0181] Example R14. The ionizer according to Examples R9 to R13, wherein the surface is a grid.

[0182] Example R15. The ionizer according to Examples R9 to R14 further includes means for moving the surface relative to the ionized material.

[0183] Example R16. An ionizer according to Examples R9 to R15, wherein the surface supports a plurality of samples, the plurality of samples being spaced apart by a distance sufficient to prevent the ionized substance from simultaneously desorbing sample material from adjacent samples.

[0184] Example R17. The ionizer according to Examples R9 to R16, wherein the surface is mounted on a movable platform, the speed of which is controlled to move the sample through the ionized substance at a certain speed, such that the ionized substance does not simultaneously desorb sample material from adjacent samples.

[0185] Example R18. An ionizer according to Examples R9 to R17, wherein the velocity of the surface is sufficient to completely vaporize the sample independently of neighboring samples.

[0186] Example R19. An ionizer according to Examples R9 to R18, wherein the velocity of the surface is sufficient to increase the sample density per square millimeter on the surface.

[0187] Example R20. A method for ionizing a sample, comprising: receiving a sample; diluting the sample with water; applying the diluted sample to a grid; and passing the sample on the grid through a pulsed atmospheric pressure ionization source.

[0188] Example R21. The method according to Example R20, wherein the sample passes through the atmospheric ionization source at an adjusted speed.

[0189] Example R22. The method according to Example R20 or R21, wherein the speed of the adjustment is increased to reduce matrix effects.

[0190] Example R23. The method according to Examples R20 to R22, wherein the ionized material flow leaving the pulsed atmospheric pressure ionization source is discontinuous.

[0191] Example R24. The method according to Examples R20 to R23, wherein when the sample moves to a position before the outlet of the ionization source, the ionized mass stream begins to leave the pulsed atmospheric pressure ionization source to complete the analysis of the sample.

[0192] Example R25. The method according to Examples R20 to R24, wherein the ionized material stream leaves the pulsed atmospheric pressure ionization source and the sample enters a position close to the stream at the same time.

[0193] Example R26. The method according to Example R25, wherein the time period is temporally limited to the incomplete desorption of the sample.

[0194] Example R27. The method according to Example R26, wherein incomplete desorption results in the generation of a Gaussian-distributed ionized sample.

[0195] Example R28. The method according to Example R27, wherein the Gaussian distribution of the sample-related ions enables the collection of more uniform data packets.

[0196] Example R29. The method according to Example R28, wherein a statistical analysis procedure can be used to process uniform data packets without background subtraction of the data collected when the sample, which is normally present on the grid, is completely desorbed.

[0197] Example R30. The method according to Example R29, wherein the results of statistical analysis are improved by using the more uniform data packets.

[0198] Example R31. The method according to Example R30, wherein the ionized material stream exits the pulsed atmospheric pressure ionization source discontinuously, which enables a reduction in the gas volume required for analysis.

[0199] Example R32. The method according to Example R31, wherein the volume of carrier gas required for sample desorption and ionization in the DART experiment is reduced by more than 95%.

[0200] Example R33. The method according to Example R32, wherein the use of a carrier gas pulse eliminates the generation of ions unrelated to the sample present on the grid.

[0201] Example R34. According to the method of Example R33, the use of the carrier gas pulse (to generate the ionized material) can be combined with a pulse of the second carrier gas to allow selective ionization of different substances present in the sample by the reaction of the ionized sample with the second gas, commonly referred to as a dopant.

[0202] Example R35. An atmospheric ionization device comprising: a mesh suitable for contacting a sample; a carrier gas supply source suitable for generating a pulsed carrier gas; a first atmospheric pressure chamber having an inlet of the pulsed carrier gas, a first electrode therein, and a counter electrode for generating a discharge in the pulsed carrier gas to produce at least a metastable neutral excited state substance; an outlet port for guiding ionized substance formed in the atmosphere toward the mesh; and a spectrometer for analyzing sample ions formed by the interaction of the ionized substance with the sample on the mesh.

[0203] Example S1. A pulsed flow atmospheric pressure ionization device for ionizing a sample, comprising: a first atmospheric pressure chamber, the first atmospheric pressure chamber including: an inlet for a carrier gas; a first electrode; a counter electrode; and an outlet port; a power source configured to energize the first electrode and the counter electrode to provide current between the first electrode and the counter electrode to generate a discharge; and a pressure regulator configured to introduce two or more carrier gas pulses into the first atmospheric pressure chamber, wherein the two or more pulses are spaced apart by a time t, wherein the power source operates continuously during the time t, wherein when each of the two or more carrier gas pulses interacts with the discharge, one or more ionized substances are generated, wherein gas contact between the one or more ionized substances and the pulsed carrier gas guides the one or more ionized substances formed in the atmosphere toward the sample through the outlet port, thereby forming ions of the sample.

[0204] Example T1. A pulsed flow atmospheric pressure ionization device for ionizing a sample, comprising: a first atmospheric pressure chamber, the first atmospheric pressure chamber including: an inlet for a carrier gas; a first electrode; a counter electrode; and an outlet port; a power source configured to energize the first electrode and the counter electrode to provide current between the first electrode and the counter electrode to generate a discharge; and a pressure regulator configured to introduce two or more carrier gas pulses into the first atmospheric pressure chamber, wherein the duration of the two or more carrier gas pulses is up to time t1, wherein the two or more carrier gas pulses are separated by time t2, wherein the interaction of the two or more carrier gas pulses with the discharge during time t1 generates one or more ionized substances, wherein gas contact between the one or more ionized substances and the two or more carrier gas pulses guides the one or more ionized substances formed in the atmosphere toward the sample through the outlet port, thereby forming ions of the sample.

[0205] Example T2. The sampler according to Example T1, wherein the power supply is configured to continuously energize the first electrode and the counter electrode.

[0206] Example T3. The sampler according to Example T1 or T2, wherein the one or more ionized substances comprise ions, electrons, thermal atoms, thermal molecules, free radicals, and metastable neutral excited-state substances.

[0207] Example T4. The sampler according to Examples T1 to T3, wherein the sample comprises an analyte applied to a mesh, an immersion probe, SPME fiber, a rod with a ticket, a glass or metal slide, a filament, a glass or metal rod, or a fiber or metal wire loop.

[0208] Example T5. The sampler according to Examples T1 to T4 further includes a cap at the outlet port, wherein the cap has an outlet aperture between the following two: a lower limit of approximately 0.1 mm; and an upper limit of approximately 4 mm.

[0209] Example T6. The sampler according to Examples T1 to T5, wherein the sample comprises two or more sample points, wherein a first sample point and a second sample point are separated by a distance d, wherein the two or more sample points are processed such that one or more ionized substances are directed toward the first sample point during the time t1 of the first pulse of the two or more carrier gas pulses, and the one or more ionized substances are directed toward the second sample point during the time t1 of the second pulse of the two or more carrier gas pulses.

[0210] Example T7. The sampler according to Example T6, wherein the two or more sample points are processed such that the two or more sample points remain stationary during the time t1.

[0211] Example T8. The sampler according to Example T6 or T7, wherein the two or more sample points are processed during the time t2 such that the one or more ionized substances are directed from the first sample point to the second sample point.

[0212] Example T9. The sampler according to Examples T6 to T8, wherein the two or more sample points are processed such that the two or more sample points move through the distance d during the time t2.

[0213] Example T10. The sampler according to Example T9, wherein the distance d is between a lower limit of approximately 0.5 mm and an upper limit of approximately 9 mm.

[0214] Example T11. The sampler according to Examples T1 to T6 further includes a cap having an outlet hole at the outlet port, wherein the outlet hole size is selected to produce a spatial resolution having a lower limit of approximately 0.2 mm and an upper limit of approximately 9 mm.

[0215] Example T12. The sampler according to Example T11, wherein the sample comprises two or more sample points, wherein a first sample point is separated from a second sample point by a distance d, wherein the spatial resolution is selected based on the distance d.

[0216] Example T13. The sampler according to Examples T1 to T12, wherein the generated discharge is one or more of corona discharge, arc discharge and glow discharge.

[0217] Example T14. The sampler according to Examples T1 to T13, wherein the time t1 is between the following two: a lower limit of about 0.1 seconds and an upper limit of about 10 seconds.

[0218] Example T15. The sampler according to Examples T1 to T14, wherein the time t2 is between the following two: a lower limit of about 0.1 seconds and an upper limit of about 10 seconds.

[0219] Example T16. The sampler according to Examples T1 to T15 further includes a heating element in fluid communication with the first atmospheric pressure chamber.

[0220] Example T17. The sampler according to Example T16, wherein the carrier gas passes near the heating element.

[0221] Example T18. The sampler according to Example T16 or T17, wherein the carrier gas is heated to a temperature between a lower limit of about 100°C and an upper limit of about 500°C.

[0222] Example T19. The sampler according to Examples T1 to T18 further includes a grid located at the exit port.

[0223] Example T20. The sampler according to Example T19, wherein a first potential is applied to the grid to deflect the charged material.

[0224] Example T21. The sampler according to Examples T1 to T20, wherein the carrier gas pressure is between a lower limit of about 0 psi and an upper limit of about 80 psi.

[0225] Example T22. An apparatus for analyzing a sample, comprising: a first atmospheric pressure chamber including an inlet for a carrier gas, a first electrode, a counter electrode, and an outlet port; a power source configured to energize the first electrode and the counter electrode to provide current between the first electrode and the counter electrode to generate a discharge; a pressure regulator configured to introduce a carrier gas into the first atmospheric pressure chamber to generate two or more carrier gas pulses, wherein the duration of the two or more carrier gas pulses is up to time t1, wherein the two or more carrier gas pulses are spaced apart by time t2, wherein the interaction of the two or more carrier gas pulses with the discharge during time t1 generates one or more ionized substances, wherein contact between the one or more ionized substances and the gas between the two or more carrier gas pulses guides the one or more ionized substances formed in the atmosphere toward a sample through the outlet port to generate one or more sample ions; and a spectrometer for analyzing the one or more sample ions.

[0226] Example T23. The apparatus according to Example T22, wherein the power supply is configured to continuously energize the first electrode and the counter electrode.

[0227] Example T24. The apparatus according to Example T22 or T23, wherein the one or more ionized substances comprise ions, electrons, thermal atoms, thermal molecules, free radicals, and metastable neutral excited-state substances.

[0228] Example T25. The apparatus according to Examples T22 to T24, wherein the sample comprises an analyte applied to a mesh, an immersion probe, SPME fiber, a rod with a ticket, a glass or metal slide, a filament, a glass or metal rod, or a fiber or metal wire loop.

[0229] Example T26. The apparatus according to Examples T22 to T25 further includes a gas ion separator.

[0230] Example T27. The apparatus according to Examples T22 to T26, wherein the gas ion separator increases the peak abundance of one or more sample ions relative to low-mass ions.

[0231] Example T28. An apparatus for analyzing a sample, comprising a first atmospheric pressure chamber including a carrier gas inlet, a first electrode, a counter electrode, and an outlet port; a power source configured to energize the first electrode and the counter electrode to provide current between the first electrode and the counter electrode to generate a discharge; a pressure regulator configured to introduce carrier gas into the first atmospheric pressure chamber to generate two or more carrier gas pulses, wherein the duration of the two or more carrier gas pulses is up to time t1, wherein the two or more carrier gas pulses are separated by time t2, wherein the interaction of the two or more carrier gas pulses with the discharge during time t1 generates one or more ionized substances, wherein gas contact between the one or more ionized substances and the two or more carrier gas pulses guides the one or more ionized substances formed in the atmosphere toward the sample through the outlet port to generate one or more sample ions; and a spectrometer for generating mass chromatography from the analysis of the one or more sample ions.

[0232] Example T29. The apparatus according to Example T28, wherein the power supply is configured to continuously energize the first electrode and the counter electrode.

[0233] Example T30. The apparatus according to Example T28 or T29, wherein the one or more ionized substances comprise ions, electrons, thermal atoms, thermal molecules, free radicals, and metastable neutral excited-state substances.

[0234] Example T31. The apparatus according to Examples T28 to T30, wherein the sample comprises an analyte applied to a mesh, an immersion probe, SPME fiber, a rod with a ticket, a glass or metal slide, a filament, a glass or metal rod, or a fiber or metal wire loop.

[0235] Example T32. The apparatus according to Examples T28 to T31, wherein the sample comprises two or more sample points, wherein a first sample point and a second sample point are separated by a distance d, wherein the two or more sample points are processed such that the one or more ionized substances are directed toward the first sample point during the time t1 of the first pulse of the two or more carrier gas pulses, and the one or more ionized substances are directed toward the second sample point during the time t1 of the second pulse of the two or more carrier gas pulses.

[0236] Example T33. The apparatus according to Examples T28 to T32, wherein the two or more sample points are processed such that the two or more sample points remain stationary during the time t1.

[0237] Example T34. The apparatus according to Examples T28 to T33, wherein the two or more sample points are processed during the time t2, such that the one or more ionized substances are directed from the first sample point to the second sample point.

[0238] Example T35. The apparatus according to Examples T28 to T34 further includes a gas ion separator.

[0239] Example T36. The apparatus according to Example T35, wherein the gas ion separator increases the peak abundance of one or more sample ions relative to low-mass ions.

[0240] Example T37. The apparatus according to Examples T28 to T36, wherein no background ions are detected during time t2.

[0241] Example T38. The apparatus according to Examples T28 to T37, wherein the relative peak abundance corresponding to the background ion is between a lower limit of about 0.01 and an upper limit of about 0.1, compared to the peak abundance corresponding to the one or more sample ions detected by the spectrometer for the first sample point.

[0242] Example T39. The apparatus according to Examples T28 to T38, wherein one or more sample ions detected by the spectrometer are detected during time t1.

[0243] Example T40. The apparatus according to Examples T28 to T39, wherein one or more sample ions corresponding to the first sample point detected by the spectrometer are detected during time t1.

[0244] Example T41. The apparatus according to Examples T28 to T40, wherein the peak abundance corresponding to one or more sample ions detected by the spectrometer for the first sample point is detected between a lower limit of approximately 0.9 × t1 seconds and an upper limit of approximately 1.1 × t1 seconds.

[0245] Example T42. The apparatus according to Examples T28 to T41, wherein one or more peaks in the mass chromatogram do not require peak detection.

[0246] Example T43. The apparatus according to Examples T28 to T42, wherein the peak abundance during time t1 eliminates the need for peak detection.

[0247] Example T44. The apparatus according to Examples T28 to T43, wherein the mass chromatograms of a plurality of samples are stored in a data file.

[0248] Example T45. A method for ionizing an analyte using a pulsed-flow atmospheric pressure ionization device, comprising: (a) energizing a first electrode relative to a second electrode spaced apart from a first electrode, wherein the first electrode and the second electrode are located in a chamber, wherein the chamber includes a gas inlet and an outlet, wherein energizing the first electrode relative to the second electrode generates a discharge; (b) introducing two or more carrier gas pulses into the chamber through the gas inlet, wherein the duration of the two or more carrier gas pulses is time t1, wherein the two or more carrier gas pulses are spaced apart by time t2; (c) generating ions, electrons, and excited-state substances from the two or more carrier gas pulses; and (d) directing the ions, electrons, and excited-state substances toward the analyte.

[0249] Example T46. The method according to Example T45, wherein the second electrode is continuously energized relative to the first electrode during time t1+t2.

[0250] Example T47. The method according to Example T45 or T46, wherein the analyte comprises a first sample point and a second sample point, wherein the first sample point and the second sample point are separated by a distance d, further comprising (e) processing the first sample point and the second sample point such that the ions, electrons, and excited-state substances are directed toward the first sample point during a first pulse of the two or more carrier gas pulses, and the ions, electrons, and excited-state substances are directed toward the second sample point during a second pulse of the two or more carrier gas pulses.

[0251] Example T48. The method according to Example T47 further includes (f) keeping the first sample point stationary during a first time period of duration t1.

[0252] Example T49. The method according to Example T48 further includes (g) keeping the second sample point stationary during a second time period of duration t1.

[0253] Example T50. The method according to Example T49 further includes (h) moving from the first sample point to the second sample point during time t2.

[0254] This document has described exemplary embodiments of the methods, systems, and components of the present invention. As otherwise indicated elsewhere, these exemplary embodiments are described for illustrative purposes only and not for limiting purposes. Other embodiments are also possible and are covered by the present invention. Such embodiments will be apparent to those skilled in the art based on the teaching contained herein. For example, it is conceivable that, regardless of the actual shapes depicted in the foregoing figures and embodiments, the outer diameter outlet of the inlet pipe may be tapered or non-tapered, and the outer diameter inlet of the outlet pipe may be tapered or non-tapered.

[0255] Therefore, the breadth and scope of the present invention should not be limited to any of the exemplary embodiments described above, but should be defined only by the following claims and their equivalents.

Claims

1. An ionizer for pulsed atmospheric ionization of a sample, comprising: The first atmospheric pressure chamber comprises: Carrier gas inlet; First electrode; Counter electrode; as well as Export port; A power source configured to energize the first electrode and the counter electrode to provide current between the first electrode and the counter electrode to generate a discharge; as well as A pulse generator configured to introduce carrier gas pulses into the first atmospheric pressure chamber to generate two or more carrier gas pulses that form ions in the sample.

2. The ionizer according to claim 1, wherein the duration of the two or more carrier gas pulses reaches time t1.

3. The ionizer according to claim 1 or 2, wherein the two or more carrier gas pulses are spaced apart by a time t2.

4. The ionizer according to claim 2, wherein the interaction of the two or more carrier gas pulses with the discharge during time t1 generates one or more ionized substances.

5. The ionizer of claim 4, wherein the one or more ionized substances are contacted with the gas between the two or more carrier gas pulses, and the one or more ionized substances formed in the atmosphere are guided to the sample through the outlet port.

6. The ionizer of claim 2, wherein the power source is configured to continuously energize the first electrode and the counter electrode.

7. The ionizer according to claim 4, wherein the one or more ionized substances comprise ions, electrons, thermal atoms, thermal molecules, free radicals, and metastable neutral excited-state substances.

8. The ionizer of claim 2, wherein the sample comprises an analyte applied to a mesh, an immersion probe, SPME fiber, a glass or metal slide, a filament, a glass or metal rod, or a fiber or metal wire ring.

9. The ionizer of claim 2, further comprising a cap located at the outlet port, wherein the cap has an outlet orifice between the following two: The lower limit is 0.1 mm; and The upper limit is 4 mm.

10. The ionizer of claim 4, wherein the sample comprises two or more sample points, wherein the first sample point and the second sample point are separated by a distance d, wherein the two or more sample points are processed such that the one or more ionized substances are directed toward the first sample point during the time t1 of the first pulse of the two or more carrier gas pulses, and the one or more ionized substances are directed toward the second sample point during the time t1 of the second pulse of the two or more carrier gas pulses.

11. The ionizer of claim 10, wherein the two or more sample points are processed such that the two or more sample points remain stationary during the time t1.

12. The ionizer of claim 10, wherein the two or more sample points are processed during the time t2 such that the one or more ionized substances are directed from the first sample point to the second sample point.

13. An apparatus for ionizing a sample, comprising: The first atmospheric pressure chamber comprises: Carrier gas inlet; First electrode; Counter electrode; as well as Export port; A power source configured to energize the first electrode and the counter electrode to provide current between the first electrode and the counter electrode to generate a discharge; as well as A pulse generator is configured to introduce a carrier gas into the first atmospheric pressure chamber to generate two or more carrier gas pulses, wherein the duration of the two or more carrier gas pulses is up to time t1, wherein the two or more carrier gas pulses are separated by time t2, wherein the interaction of the two or more carrier gas pulses with the discharge during time t1 generates one or more ionized substances, wherein the gas contact between the one or more ionized substances and the two or more carrier gas pulses guides the one or more ionized substances formed in the atmosphere toward the sample through the outlet port, thereby generating one or more sample ions.

14. The apparatus of claim 13, wherein the power source is configured to continuously energize the first electrode and the counter electrode.

15. A method for ionizing an analyte using a pulsed-current atmospheric pressure ionization device, comprising: (a) The first electrode is energized relative to a second electrode spaced apart from the first electrode, wherein the first electrode and the second electrode are located in a chamber, wherein the chamber includes a gas inlet and an outlet, wherein energizing the first electrode relative to the second electrode generates a discharge; (b) Introducing two or more carrier gas pulses into the chamber through a gas inlet, wherein the duration of the two or more carrier gas pulses is time t1, and wherein the two or more carrier gas pulses are separated by time t2; (c) Ions, electrons, and excited-state matter that generate the two or more carrier gas pulses; and (d) Direct the ions, electrons, and excited-state substances toward the analyte.

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